Gene expression and the tempo and mode of protein evolution

Evolution is the driver of the awe-inspiring biodiversity surrounding us, but is not without limits. At the molecular level, gene expression levels may constrain protein evolution. This project will address to what extent expression constrains or facilitates the evolution of TEM-1 ß-lactamase, an important antibiotic resistance conferring protein.


The aim of this project is to investigate to what extent the tempo and mode of evolution of the enzyme TEM-1 ß-lactamase in the presence of a novel antibiotic are influenced by its expression level. Ultimately, our results could shine light on the effect of expression on protein evolution, and provide insights in the dynamics and repeatability of the evolution of antibiotic resistance.


To study the role of expression in the evolution of the antibiotic-resistance enzyme TEM-1 ß-lactamase, we will vary the expression level of TEM-1 using a tunable promoter and perform a series of evolution experiments, where TEM-1 alone or TEM-1 together with its promoter sequence will evolve towards increased cefotaxime resistance. By measuring resistance and fitness and sequencing selected TEM alleles throughout the evolution experiments, we determine the evolutionary dynamics (tempo) and preferred mutational pathways (mode) associated with different expression levels. Finally, to provide a deeper layer of understanding of the relevant constraints we want to determine the activity, thermostability and the effects on fitness of the selected variants.

Student Opportunities

We are open to applications for thesis projects! We have different thesis topics available, including projects with Experimental Evolution, Antibiotic Resistance, Molecular Biology.

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